The personal computer (PC) has become a common feature of everyday business and domestic life. From document creation and sharing to scheduling and messaging; personal computers have become part of the way people communicate and interact. As personal computers have become more useful, personal computer users have come to demand that their computers be available whenever and wherever they are.
Mobile personal computers have the potential to make personal computing more available than ever before but typically, the availability of a mobile personal computer is constrained by its limited mobile power supply. If the power supply runs out, the computer becomes unavailable. As a result, a mobile personal computer user seeking to maximize availability may need to monitor and conserve the mobile power supply. At times, for example, when power consumption associated with a task is high, maintaining even modest availability may require significant effort.
Power conservation schemes for conventional mobile personal computers typically involve the computer user manually switching the computer to a working state with relatively high power consumption when attentively working with the computer and then switching the computer to a sleeping or off state with relatively low power consumption otherwise. There are variations on this theme, for example, the computer may determine (at times mistakenly) that the computer user is not attentive enough to justify the high power consumption of the working state and then automatically switch to the sleeping or off state. A problem with such schemes is that they leave the computer effectively unavailable whenever the computer user is not attentively working with the computer. For example, events and alerts that occur during this period of unavailability may not be brought timely to the attention of the computer user and useful background work may be delayed thus lowering efficiency.